Haploidie bei einer Spinnmilbe

Schradér, Franz

doi:10.1007/bf02977822

Cited by 47 publications

(10 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…16-17). SCHRADER (1923) observed three bivalents of identical shape and size in the cortex of eggs in T. urticae just after oviposition. In telophase of the first maturation division there are two groups of three chromosomes, the double structure of which is very clear.…”

Section: Translocation Heterozygotesmentioning

confidence: 96%

See 1 more Smart Citation

Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (Tetranychidae, trombidiformes). I: Meiosis in eggs

Feiertag-Koppen

1976

Genetica

View full text Add to dashboard Cite

Meiosis in eggs of Tetranychus urticae Koch is described. The two maturation divisions result in (a) a haploid female pronucleus consisting of three karyomeres; -(b) a divided first polar body in which the chromosomes change into karyomeres; -(c) a second polar body, entering a new mitosis which is blocked in metaphase. Irradiation of adult females produced chromosome fragments in the meiotic divisions. The fragments behave as intact chromosomes which proves that during meiosis a diffuse kinetochore is present. The meiotic divisions show the cytologically characteristic features of an inverted meiosis. The presence of such a meiosis is corroborated by observations on eggs heterozygous for chromosome mutations. In both maturation divisions the chromosomes are orientated equatorially. It is suggested that the equatorial orientation is brought about by chiasmata having terminalized to both ends of the dyads. It is argued that in organisms with holokinetic chromosomes during meiosis an axial orientation of the bivalents does not necessarily imply a normal meiosis but can also imply an inverted meiosis.

show abstract

Section: Translocation Heterozygotesmentioning

confidence: 96%

“…Only SCHRADER (1923) investigated the oogenesis of T. urticae; particularly with regard to the arrhenotokous reproduction. He described the meiosis from first metaphase onwards, which takes place in the eggs just after oviposition.…”

Section: Introductionmentioning

confidence: 99%

Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (Tetranychidae, trombidiformes). I: Meiosis in eggs

Feiertag-Koppen

1976

Genetica

View full text Add to dashboard Cite

show abstract

“…In tetranychids, virgin females pro duce only male progeny; mated females produce both sexes, but usually a high percentage of females. Schrader (1923) distinguished two types of eggs and lar vae in Tetranychus urticae: with three and six chromosomes, respectively. Schrader concluded that males develop from unfertilized eggs and are haploid, whereas females develop from fertilized eggs and are diploid.…”

Section: Sex Ratios and Sex Determinationmentioning

confidence: 99%

Ecology of tetranychid mites and their natural enemies: A review: III. Biology, ecology, and pest status, and host-plant relations of tetranychids

Vrie¹,

McMurtry²,

Huffaker³

1972

Hilg

275

View full text Add to dashboard Cite

The literature pertalOlOg to the bionomics of some of the mos t important tetranychids is r~viewed. Considerable attention is paid to the possihiliries of spider mites reaching pest le~els /as a 'resu lt of environmental factors. It is concluded that more infor--m ation is needed on economic injury levels of various species on d ifferent crops and under various climatic conditions. The in-I fluences of cultural practices and their interactions as related to population development of tetranychids also need more i tu dy. Furthermore, work is need~d on the influence of climatic conditions on development of retranychid mite populations together with possible predictability 'of outbreak situations. Finally; we need to know more about ·th)e fundamental relations between the host-planr-qualiry and spider mite development, and the, impact of spider mites on the development .of their .host p lants.

show abstract

“…Females develop from fertilized eggs and are diploid (Schrader, 1923;Helle & Overmeer, 1973). urticae reproduces by arrhenotokous parthenogenesis, males are haploid developing from unfertilized eggs.…”

mentioning

confidence: 99%

“…urticae reproduces by arrhenotokous parthenogenesis, males are haploid developing from unfertilized eggs. Females develop from fertilized eggs and are diploid (Schrader, 1923;Helle & Overmeer, 1973). Because of the arrhenotokous parthenogenesis, genes with a positive selective advantage are readily selected for (Helle, 1965).…”

mentioning

confidence: 99%

MATING COMPETITIVENESS AND THE EFFECT OF X‐RAYS AND AGEING ON MALES OF TETRANYCHUS URTICAE (ACARINA, TETRANYCHIDAE) IN RELATION TO GENETIC CONTROL

Feldmann¹

1977

Entomologia Exp Applicata

View full text Add to dashboard Cite

Males of Tetranychus urticae Koch were irradiated with X-ray doses of 4, 8, 24 and 32 krad (were applied to 0-1 day-old adult virgin males) and tested in mating competition with one-day-old nonirradiated males. A non-significant excess of parental females were mated to the unirradiated males. This consistent trend in favour of females, mated with unirradiated males was highly significant, when the results of all the experiments were bulked. This indicated that radiation impaired the mating competitiveness of males of T. urticae. Ageing of irradiated males resulted in a significant decrease of male-mating competitiveness at least within 2 days after irradiation. When 24 krad X-rays irradiated males were tested in mating competition at different ages, with unirradiated males of equal age, it was demonstrated that the reduction in mating competitiveness of ageing irradiated males is caused by accelerated ageing, due to the irradiation treatment.

show abstract

Haploidie bei einer Spinnmilbe

Cited by 47 publications

References 8 publications

Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (Tetranychidae, trombidiformes). I: Meiosis in eggs

Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (Tetranychidae, trombidiformes). I: Meiosis in eggs

Ecology of tetranychid mites and their natural enemies: A review: III. Biology, ecology, and pest status, and host-plant relations of tetranychids

MATING COMPETITIVENESS AND THE EFFECT OF X‐RAYS AND AGEING ON MALES OF TETRANYCHUS URTICAE (ACARINA, TETRANYCHIDAE) IN RELATION TO GENETIC CONTROL

Contact Info

Product

Resources

About